With the proportion of people 65 and older expected to rise to 22% by 2020, it is critical to develop and test population-based approaches for large scale, effective health promotion for our aging society. This will permit evidence-based decisions as to how to deploy resources in order to have optimal impact on the health of older adults. This project seeks to contribute toward this goal, within a broader program project, by conducting a randomized, controlled trial of the effectiveness of the Experience Corps program in preventing or delaying physical disability, falls and cognitive decline in older volunteers. This program is a senior volunteer program which places people 60 and older in meaningful roles in public elementary schools designed to have high impact on childrens' outcomes; the program attracts and retains older adults, 15 hours per week, for its opportunity to give back. However, designed into the program is a health promotion program, intended to increase social, cognitive and physical activity. Building on a successful pilot in Baltimore, MD, the Mayor supports scaling the program up across the city. This proposal will, in a University-community collaboration, conduct a rigorous evaluation of the impact of the scaled-up program through an evaluation of older volunteers randomized to the Experience Corps or a control group (low commitment volunteering) for 2 years. Secondary aims are to determine if Experience Corps participation preserves or slows loss of strength, balance, cortical plasticity and executive function and prevents frailty and declines in IADL performance. All adults randomized to Experience Corps or controls will be followed for 2 years; those enrolled in the first year will be followed for 3 years. Given the demonstrated diversity of older adults attracted to Experience Corps service, this will provide insight into the potential of this social model for health promotion through generativity to help resolve health disparities for older adults. The work of this project will be mutually interconnected and synergistic with the other 4 projects in this Program Project, interconnecting through a Steering Committee in Core A. A Recruitment and Retention Core (Core B), a Data Collection and Management Core (Core C) and a Design, Randomization and Analysis Core (Core D) will support the conduct of the project. Overall, this program project is designed to evaluate the utility and effectiveness of Experience Corps as a social model for health promotion for an aging society.